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Home >> Toyota >> 2003 >> Matrix Base, FWD, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 86 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P2A00: A/F Sensor Circuit Slow Response (Bank 1 Sensor 1) & DTC P2A03: A/F Sensor Circuit Slow Response (Bank 2 Sensor 1) >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. If any other codes besides DTCs P2A00 or P2A03 are output, go to relevant DTC test. If not, go to next step.
  2. Connect OBD-II scan tool or hand-held tester to DLC3. Warm up the A/F sensors (bank 1, 2 sensor 1) with the engine at 2500 RPM for approximately 90 seconds. On hand-held tester, select ENHANCED OBD2/SNAPSHOT/MANUAL SNAP SHOT/ ALL mode. On either tester, read the voltage of A/F sensors (bank 1, 2 sensor 1) on the screen of the OBD-II scan tool or hand-held tester when performing all the following conditions. See Figure-Figure . Voltage of AFR(+) - E1 (-) or AFL(+) - E1 (-) terminals of ECM is fixed at 3.3 volts and voltage of terminals AFR (-) - E1 or AFL (-) - E1 (-) is fixed at 3.0 volts. If system is okay, go to step  12. If system is not okay, go to next step.
    NOTE: Under normal condition, when the vehicle is driven, in the case that the output voltage of the A/F sensors is below 2.8 volts on hand-held tester, or 0.76 volts on OBD-II scan tool, during fuel enrichment (for example, when the vehicle tries to overtake another vehicle on a highway, the vehicle speed is suddenly increased with the accelerator pedal fully depressed), the A/F sensors are functioning normally. Under malfunction condition, whenever the output voltage of the A/F sensors remains at approximately 3.3 volts for hand-held tester, or 0.660 volts for OBD-II tester under any conditions as well as the above conditions, the A/F sensors may have an open circuit. This will happen also when the A/F sensor heater has an open-circuit. Whenever the output voltage of the A/F sensors remains at a certain value of approximately 3.8 volts or more for hand-held tester or 0.76 volts or more for OBD-II scan tool, or 2.8 volts or less for hand-held tester or 0.56 volts or less OBD-II scan tool under any conditions as well as the above conditions, the A/F sensor may have a short-circuit.
  3. Check for open and short in harness and connector between ECM and A/F sensors (bank 1 and/or 2 sensor 1). Repair or replace harness or connector as necessary. If harness or connector are okay, go to next step.
  4. Check resistance of A/F sensor heater. See SENSOR OPERATING RANGE CHARTS article. Replace as necessary. If A/F sensor is okay, go to next step.
  5. Check air induction system. See AIR INDUCTION SYSTEMS in SYSTEM & COMPONENT TESTING - ES300 & RX300 article. Repair or replace as necessary. If okay, go to next step.
  6. Check fuel pressure. Check and repair fuel pump, fuel pipe line and filter as necessary. If okay, go to next step.
  7. Check injector injection. Replace injector as necessary. If injector is okay, go to next step.
  8. Replace A/F sensor (bank 1 and/or 2 sensor 1). Go to next step.
  9. Perform confirmation driving pattern. See CONFIRMATION DRIVING PATTERN  under DTC P0134 & P0154.
  10. If DTC P2A00 and/or P2A03 are output again, check and replace ECM. If not, go to next step.
  11. Check if vehicle ran out of fuel in the past. If not, check for intermittent problems. If yes, DTC P2A00 and/or P2A03 are caused by running out of fuel.
  12. Perform confirmation driving pattern. See CONFIRMATION DRIVING PATTERN  under DTC P0134 & P0154. Go to next step.
  13. If DTC P2A00 and/or P2A03 are output again, go to next step. If not, go to step  17.
  14. Replace A/F sensor (bank 1 and/or 2 sensor 1). Go to next step.
  15. Perform confirmation driving pattern. See CONFIRMATION DRIVING PATTERN  under DTC P0134 & P0154. Go to next step.
  16. If DTC P2A00 and/or P2A03 are output again, check and replace ECM. If not, go to next step.
  17. Determine whether vehicle ran out of fuel in the past. If not, check for intermittent problems. If yes, go to next step.
  18. DTC P2A00 and/or P2A03 were caused by running out of fuel.
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